With the development and promotion of renewable energy sources such as solar and wind, efficient energy storage systems are becoming increasingly important in the mix. Bidirectional DC/DC converter is a key device for energy conversion between battery bank and DC bus, which directly affects the efficiency, power density and reliability of the system. However, conventional single-phase CLLC converters face limitations in high-power applications, where large magnetic components restrict performance improvement. In this paper, a three-phase interleaved bi-directional CLLC converter with vertically integrated magnetic components is proposed, which utilizes a three-phase interleaving technique to connect three CLLC converters in parallel with a phase shift of 120°, resulting in a reduction of current ripple and an increase in power rating. Meanwhile, the integration of all inductor and transformer cores in the converter can realize magnetic flux offset, reducing core loss and component size. In this paper, a symmetrical three-phase perpendicular magnetic integrated structure is designed by analyzing its magnetic reluctance model, and the core and winding losses are reduced by optimizing the geometrical parameters in order to minimize the losses and volume. Validated by simulations in MATLAB/Simulink and ANSYS Maxwell, this design reduces core losses by 39% and core height by 25%, significantly increasing power density.